Kill Tumor Cells Research Articles

Immunomodulatory effects of trastuzumab deruxtecan through the cGAS-STING pathway in gastric cancer cells

Although the efficacy of trastuzumab deruxtecan (T-DXd) against HER2-positive gastric cancers (GCs) has driven its clinical application, the precise mechanisms governing its immunomodulatory role remain unclear. In this study, we examined the immune-related mechanisms of action of T-DXd in GC cells. T-DXd exhibited potent antitumor effects in GC cells across diverse HER2 expression levels by inducing DNA damage and apoptosis. Activation of the DNA damage response by T-DXd led to increased PD-L1 expression. RNA-Seq analysis revealed that T-DXd modulated immune-related pathways, resulting in the upregulation of genes associated with inflammation and IFN signaling. Importantly, T-DXd activated the cGAS-STING pathway, inducing an IFN-I response in HER2-positive GC cells. Furthermore, T-DXd activated dendritic cells via the cancer cell-intrinsic cGAS-STING-IFN axis and enhanced PBMC-mediated tumor cell killing by activating CD8+ T cells. These findings provide valuable insights into the role of the cytosolic DNA sensing pathway in the action of T-DXd and offer a compelling rationale for combining T-DXd with immune checkpoint blockade therapies in GC treatment.

A splicing isoform of PD-1 promotes tumor progression as a potential immune checkpoint

The immune checkpoint receptor, programmed cell death 1 (PD-1, encoded by PDCD1), mediates the immune escape of cancer, but whether PD-1 splicing isoforms contribute to this process is still unclear. Here, we identify an alternative splicing isoform of human PD-1, which carries a 28-base pairs extension retained from 5′ region of intron 2 (PD-1^28), is expressed in peripheral T cells and tumor infiltrating lymphocytes. PD-1^28 expression is induced on T cells upon activation and is regulated by an RNA binding protein, TAF15. Functionally, PD-1^28 inhibits T cell proliferation, cytokine production, and tumor cell killing in vitro. In vivo, T cell-specific exogenous expression of PD-1^28 promotes tumor growth in both a syngeneic mouse tumor model and humanized NOG mice inoculated with human lung cancer cells. Our study thus demonstrates that PD-1^28 functions as an immune checkpoint, and may contribute to resistance to immune checkpoint blockade therapy.

Combining ERAP1 silencing and entinostat therapy to overcome resistance to cancer immunotherapy in neuroblastoma

BackgroundCheckpoint immunotherapy unleashes tumor control by T cells, but it is undermined in non-immunogenic tumors, e.g. with low MHC class I expression and low neoantigen burden, such as neuroblastoma (NB). Endoplasmic reticulum aminopeptidase 1 (ERAP1) is an enzyme that trims peptides before loading on MHC class I molecules. Inhibition of ERAP1 results in the generation of new antigens able of inducing potent anti-tumor immune responses. Here, we identify a novel non-toxic combinatorial strategy based on genetic inhibition of ERAP1 and administration of the HDAC inhibitor (HDACi) entinostat that increase the immunogenicity of NB, making it responsive to PD-1 therapy.MethodsCRISPR/Cas9-mediated gene editing was used to knockout (KO) the ERAP1 gene in 9464D NB cells derived from spontaneous tumors of TH-MYCN transgenic mice. The expression of MHC class I and PD-L1 was evaluated by flow cytometry (FC). The immunopeptidome of these cells was studied by mass spectrometry. Cocultures of splenocytes derived from 9464D bearing mice and tumor cells allowed the assessment of the effect of ERAP1 inhibition on the secretion of inflammatory cytokines and activation and migration of immune cells towards ERAP1 KO cells by FC. Tumor cell killing was evaluated by Caspase 3/7 assay and flow cytometry analysis. The effect of ERAP1 inhibition on the immune content of tumors was analyzed by FC, immunohistochemistry and multiple immunofluorescence.ResultsWe found that inhibition of ERAP1 makes 9464D cells more susceptible to immune cell-mediated killing by increasing both the recall and activation of CD4+ and CD8+ T cells and NK cells. Treatment with entinostat induces the expression of MHC class I and PD-L1 molecules in 9464D both in vitro and in vivo. This results in pronounced changes in the immunopeptidome induced by ERAP1 inhibition, but also restrains the growth of ERAP1 KO tumors in vivo by remodelling the tumor-infiltrating T-cell compartment. Interestingly, the absence of ERAP1 in combination with entinostat and PD-1 blockade overcomes resistance to PD-1 immunotherapy and increases host survival.ConclusionsThese findings demonstrate that ERAP1 inhibition combined with HDACi entinostat treatment and PD-1 blockade remodels the immune landscape of a non-immunogenic tumor such as NB, making it responsive to checkpoint immunotherapy.

Cancer new treatment series: Comparison immune changes of HCC by scRNA-Seq following HELC treatment one case study

Immunotherapy has emerged as a novel treatment strategy for many types of cancers, among them, liver cancer. The major advances and achievements in recent years is the use of programmed death-1 (PD-1) blockers for cancer treatment. Since patients’ immune systems are already weak following concurrent surgery plus chemo or radiotherapy, it is necessary to restore and awake their immune cells to maximize the effect for immune therapy. Methods: Liver cancers were treated twice with hapten enhanced local chemotherapy (HELC) like tumor lysates vaccine and following PD-1. Single-cell RNA sequencing (scRNA-seq) was used to analyze the changes of immune responses prior and after treatments. Results: We observed upregulation of cytotoxicity-related genes of CD8 effector T cells and NK cells in untreated tumor; Both Bmem and Naive B cells in untreated tumor showed a significant increase in MHC II signaling pathway-related genes, while MHC I-related genes was upregulated in plasma cells. Significant tumor size shrinkage was observed in both treated and untreated tumors following the HELC+PD-1 therapy. Conclusions: This study provides new biological insights into the abscopal effect at the single-cell level related to the composition of T and B cells in untreated liver cancers before and after major primary tumors treated by HELC. Our data showed that intra-tumor HELC can kill tumor cells and induced immune activity, which is likely vital in modifying tumor associate antigens (TAAs) into neo TAAs. It induces immune response just like vaccine can wake up immune cells and therefore increasing the efficacy of PD1 therapy.

Abstract A052: RNF43 p.G659fs mutation in MSI-high colorectal cancer leads to natural killer cell dysfunction

Abstract RNF43_p.G659fsV*41 mutation (RNF43659mut) is found in approximately 8% of colorectal cancers (CRCs) and is enriched in microsatellite-instability high (MSI-high) tumors. Previously, we reported that RNF43659mut promotes tumor growth independent of WNT signaling and activates PI3K/AKT signaling in CRC, conferring vulnerability to PI3K/MTOR inhibition. In addition, RNF43659mut was associated with decreased interferon signaling suggesting a link with anti-tumor immunity. Thus, in the current work we investigated the role of RNF43659mut in CRC immunomodulation. The immune-cell landscape was evaluated in RNF43659mut compared with RNF43-wild type (wt) MSI-high CRCs in two cohorts; single-cell (sc)-RNA-sequencing data from treatment-naïve primary tumors from 34 patients (cohort-1) and multiplex immunofluorescence / whole exome sequencing data from an independent cohort of 91 patients (cohort-2). Healthy donor blood-derived natural killer (NK) cell responses and cytotoxicity were investigated in co-cultures with RNF43659mut isogenic tumor lines and with patient-derived organoids harboring RNF43659mut or overexpressing RNF43wt. A third patient cohort with MSI-high CRCs treated with immune checkpoint blockade was analyzed to understand the impact of RNF43659mut on immunotherapy efficacy. Interrogation of sc-RNASeq data in cohort-1 revealed a significant enrichment of NK cells in the RNF43659mut patient samples compared to the RNF43wt ones. This finding was also confirmed by multiplex immunofluorescence in cohort-2. Single-cell transcriptomic analyses in cohort-1 showed increased inhibitory markers on NK cells despite their enrichment in RNF43659mut tumors. RNAseq analysis of sorted NK cells co-cultured with RNF43659mut isogenic tumor lines further supported their dysfunctional state. Flow cytometric analyses of NK cell maturation, activation, and inhibitory markers in NK cells co-cultured with RNF43659mut isogenic tumor lines and organoids highlighted decreased levels of NCAM1 (CD56)dim and NCAM1 (CD56)bright subsets, FCGR3A (CD16), and KLRK1 (NKG2D), along with increased levels of KLRC1 (NKG2A), KIR3DL1 (NKB1) and TIGIT inhibitory markers. There was reduced NK cell mediated tumor cell killing in RNF43659mut isogenic tumor lines and organoids. We postulated that aberrant signaling of the PI3K/AKT pathway with RNF43659mut could lead to NK cell dysfunction. Indeed, siRNA-mediated blocking of PI3K/AKT pathway restored the NK-cell dysfunctional phenotype and tumor cell killing in co-cultures with RNF43659mut isogenic tumor lines and organoids. Conversely, overexpression of WT RNF43 in RNF43659mut organoids downregulated PI3K/AKT signaling and increased NK cell cytotoxicity. Lastly, MSI-high CRC tumors harboring RNF43659mut in patients treated with immunotherapy showed less benefit from immune checkpoint blockade. PI3K/AKT activation due to RNF43659mut in MSI-high CRC leads to NK cell dysfunction and reduced NK cell cytotoxicity. This could be responsible for immunotherapy failure, warranting further investigation. Citation Format: Pushpamali De Silva, Samantha Fitzgerald, Jules Cazaubiel, Matan Hofree, Tomotaka Ugai, Juha P Väyrynen, Dane Ford-Roshon, Lishan Fang, Ana Garrido-Castro, Nir Hacohen, Kimmie Ng, Shuji Ogino, Jonathan A Nowak, Marios Giannakis. RNF43 p.G659fs mutation in MSI-high colorectal cancer leads to natural killer cell dysfunction [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor Immunology and Immunotherapy; 2024 Oct 18-21; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2024;12(10 Suppl):Abstract nr A052.

Immune Checkpoint Inhibitors in the Emergency Department

Immune-checkpoint inhibitors (ICIs) have transformed the landscape for cancer treatment by enhancing the endogenous immune system’s ability to eliminate cancer cells. Tumor cells evade the body’s immune response by blocking T cell activation; ICIs function by blocking this inhibition, thereby boosting the immune system’s ability to kill tumor cells. Despite producing astonishing improvements in prognosis and remission-free time frames for cancer patients, ICIs carry risks for well documented treatment-related complications and immune-related adverse events (irAEs) that can be life-threatening. IrAEs can occur in almost any organ system, and they usually occur early in treatment, typically within the first three months. Some common complications involve the cutaneous, gastrointestinal tract, pulmonary, and endocrine organ systems. Guidelines outlining the general treatment algorithms for irAEs have been published by the Society for Immunotherapy of Cancer (SITC) and the National Comprehensive Cancer Network (NCCN). When patients present to the Emergency Department with symptoms consistent with irAEs, a rigorous and thorough infectious work-up is required, and treatment usually begins. This includes immunosuppression with corticosteroids, symptomatic treatment, and/or discontinuation of the ICI depending on the grade and severity of presentation. Early recognition and management of irAEs among ED providers, in conjunction with treating oncologists, are imperative to improve patient outcomes in the Emergency Department.

An Intelligent Triple Assisted Gold Cluster‐Based Nanosystem for Enhanced Tumor Photodynamic Therapy

Comprehensive SummaryPhotodynamic therapy (PDT) has been attracted a surge of research interest. However, there are several obstacles to limit the efficacy of PDT, such as hypoxic tumor microenvironment (TME), overexpressed glutathione (GSH), inefficient reactive oxygen species (ROS) generation, and so on. Herein, a smart responsive nanosystem was constructed, which was composed of Au25 modified with triphenylphosphine (Au25‐TPP), catalase (CAT) and GSH‐responsive diselenide‐bridged mesoporous silica nanoparticles (Se‐MSN). When the nanosystem arrived at tumor site, Se‐MSN was degraded by the intracellular overexpressed GSH to release Au25‐TPP and CAT. The Au25‐TPP was targeted to mitochondria and generated ROS under the 808 nm NIR laser irradiation to kill tumor cells. Simultaneously, CAT could catalyze hydrogen peroxide to provide oxygen for relieving the hypoxia of TME. Besides, GSH was consumed by the diselenide bond to diminish the ROS loss. The above tactics (mitochondria targeting, hypoxia relieving and GSH consuming) jointly enhanced the PDT efficacy. The nanosystem showed distinct in vitro anticancer effect significantly stronger than other groups containing one or two assistance. Moreover, the in vivo results suggested that the tumors could be restrained obviously. The current study provides a new inspiration for constructing novel inorganic nanomedicines with multiple enhancement effect of PDT efficacy.

Zinc-Nickel Bimetallic Hydroxide Nanosheets Activate the Paraptosis-Pyroptosis Positive Feedback Cycle for Enhanced Tumor Immunotherapy.

Immunotherapy holds significant promise for cancer treatment. However, the highly immunosuppressive nature of solid tumors limits its effectiveness. Herein, we developed bioactive zinc-nickel hydroxide (ZnNi(OH)4) nanosheets (NSs) that can effectively initiate the paraptosis-pyroptosis positive feedback cycle through synergistic ionic effect, thereby mitigating the immunosuppression of solid tumors and enhancing the efficacy of immunotherapy. The acid-sensitive ZnNi(OH)4 NSs releases Ni2+ and Zn2+ in the weakly acidic tumor microenvironment. The released Ni2+ alleviated pyroptosis inhibition by inducing paraptosis and inhibiting autophagic flux. Concurrently, Ni2+ triggered release of endogenous Zn2+ within the cell through a coordination competition mechanism, further amplifying zinc overload-mediated pyroptosis. Interestingly, pyroptosis-associated oxidative stress and endoplasmic reticulum stress further promote Ni2+-mediated paraptosis, forming a positive feedback loop between pyroptosis and paraptosis. This process not only effectively kills tumor cells but also stimulates a strong inflammatory response, enhancing the antitumor immune response and immunotherapy efficacy. Overall, this study proposes an effective paraptosis-pyroptosis induction strategy based on metal ions and demonstrates the effectiveness of the positive feedback loop of paraptosis-pyroptosis in potentiating immunotherapy.

Cytokine-armed vaccinia virus promotes cytotoxicity toward pancreatic carcinoma cells via activation of human intermediary CD56dimCD16dim natural killer cells.

Pancreatic ductal adenocarcinoma (PDAC) remains a particularly aggressive disease with few effective treatments. The PDAC tumor immune microenvironment (TIME) is known to be immune suppressive. Oncolytic viruses can increase tumor immunogenicity via immunogenic cell death (ICD). We focused on tumor-selective (vvDD) and cytokine-armed Western-reserve vaccinia viruses (vvDD-IL2 and vvDD-IL15) and infected carcinoma cell lines as well as patient-derived primary PDAC cells. In co-culture experiments, we investigated the cytotoxic response and the activation of human natural killer (NK). Infection and virus replication were assessed by measuring virus encoded YFP. We then analyzed intracellular signaling processes and oncolysis via in-depth proteomic analysis, immunoblotting and TUNEL assay. Following the co-culture of mock or virus infected carcinoma cell lines with allogenic PBMCs or NK cell lines, CD56+ NK cells were analyzed with respect to their activation, cytotoxicity and effector function. Both, dose- and time-dependent release of danger signals following infection weremeasured. Viruses effectively entered PDAC cells, emitted YFP signals and resulted in concomitant oncolysis. The proteome showed reprogramming of normally active core signaling pathways in PDAC (e.g., MAPK-ERK signaling). Danger-associated molecular patterns were released upon infection and stimulated co-cultured NK cells for enhanced effector cytotoxicity. NK cell subtyping revealed enhanced numbers and activation of a rare CD56dimCD16dim population. Tumor cell killing was primarily triggered via Fas ligands rather than granule release, resulting in marked apoptosis. Overall, the cytokine-armed vaccinia viruses induced NK cell activation and enhanced cytotoxicity toward human PDAC cells in vitro. We could show that cytokine-armed virus targets the carcinoma cells and thus hasgreat potential to modulate the TIME in PDAC.

NPM1 inhibits tumoral antigen presentation to promote immune evasion and tumor progression

BackgroundTumor cells develop multiple mechanisms to facilitate their immune evasion. Identifying tumor-intrinsic factors that support immune evasion may provide new strategies for cancer immunotherapy. We aimed to explore the function and the mechanism of the tumor-intrinsic factor NPM1, a multifunctional nucleolar phosphoprotein, in cancer immune evasion and progression.MethodsThe roles of NPM1 in tumor progression and tumor microenvironment (TME) reprogramming were examined by subcutaneous inoculation of Npm1-deficient tumor cells into syngeneic mice, and then explored by CyTOF, flow cytometry, immunohistochemistry staining, and RNA-seq. The in-vitro T-cell killing of OVA-presenting tumor cells by OT-1 transgenic T cells was observed. The interaction of NPM1 and IRF1 was verified by Co-IP. The regulation of NPM1 in IRF1 DNA binding to Nlrc5, Ciita promoter was determined by dual-luciferase reporter assay and ChIP-qPCR.ResultsHigh levels of NPM1 expression predict low survival rates in various human tumors. Loss of NPM1 inhibited tumor progression and enhanced the survival of tumor-bearing mice. Npm1-deficient tumors showed increased CD8+ T cell infiltration and activation alongside the reduced presence of immunosuppressive cells. Npm1 deficiency increased MHC-I and MHC-II molecules and specific T-cell killing. Mechanistically, NPM1 associates with the transcription factor IRF1 and then sequesters IRF1 from binding to the Nlrc5 and Ciita promoters to suppress IRF1-mediated expression of MHC-I and MHC-II molecules in tumor cells.ConclusionsTumor-intrinsic NPM1 promotes tumor immune evasion via suppressing IRF1-mediated antigen presentation to impair tumor immunogenicity and reprogram the immunosuppressive TME. Our study identifies NPM1 as a potential target for improving cancer immunotherapy.

Fine-Tuning the d-Band Center Position of Zinc to Increase the Anti-Tumor Activity of Single-Atom Nanozymes.

The exceptional biocompatibility of Zn-based single-atom nanozymes (SAzymes) has led to extensive research in their application for disease diagnosis and treatment. However, the fully occupied 3d10 electron configuration has seriously hampered the enzymatic-like activity of Zn-based SAzymes. Herein, a B-doped Zn-based SAzymes is fabricated by carbonizing zeolite-like Zn-based boron imidazolate framework at different temperatures (Zn-SAs@BNCx, x = 800, 900, 1000, and 1100°C). The formed B─N bond yielded a local electric field, which changes the position of the d-band center and improved the oxidation state of Zn by facilitating the electron transfer from Zn to N to B. These changes enhanced the adsorption and activation of H2O2 and O2 by Zn-SAs@BNC1000, increasing the nanozymes' multi-enzyme catalytic activity. B doping led to 24.81-, 32.37-, and 13.98-fold increase in the peroxidase-, oxidase- and catalase-like, respectively, catalytic efficiency (Kcat/Km) of Zn-SAs@BNC1000 when compared with no B doping. In addition, Zn-SAs@BNC1000 showed excellent ability to kill tumor cells both in vitro and in vivo. This study demonstrates that the modulation of the electron configuration of Zn is an effective strategy to develop efficient anti-tumor approaches by boosting the enzymatic activity of Zn-based SAzymes.

High-resolution and programmable RNA-IN and RNA-OUT genetic circuit in living mammalian cells

RNAs and their encoded proteins intricately regulate diverse cell types and states within the human body. Dysregulated RNA expressions or mutations can lead to various diseased cell states, including tumorigenesis. Detecting and manipulating these endogenous RNAs offers significant promise for restoring healthy cell states and targeting tumors both in research and clinical contexts. This study presents an RNA-IN and RNA-OUT genetic circuit capable dynamically sensing and manipulating any RNA target in a programmable manner. The RNA-IN module employes a programmable CRISPR-associated protease (CASP) complex for RNA detection, while the RNA-OUT module utilizes an engineered protease-responsive dCas9-VPR activator. Additionally, the CASP module can detect point mutations by harnessing an uncovered dual-nucleotide synergistic switching effect within the CASP complex, resulting in the amplification of point-mutation signals from initially undetectable levels (1.5-fold) to a remarkable 94-fold. We successfully showcase the circuit’s ability to rewire endogenous RNA-IN signals to activate endogenous progesterone biosynthesis pathway, dynamically monitor adipogenic differentiation of mesenchymal stem cells (MSCs) and the epithelial-to-mesenchmal trans-differentiation, as well as selective killing of tumor cells. The programmable RNA-IN and RNA-OUT circuit exhibits tremendous potential for applications in gene therapy, biosensing and design of synthetic regulatory networks.

Preliminary study of a compact epithermal neutron absolute flux intensity measurement system for real-time in-vivo dose monitoring in boron neutron capture therapy

Boron neutron capture therapy (BNCT) is a radiotherapy technology that selectively kills tumor cells via the 10B(n, α)7Li reactions. Epithermal neutrons (0.5 eV–10 keV) are emitted and converted into thermal neutrons, which have a larger neutron capture reaction cross-section, by slowing down in the human body before reaching the tumor. Recently, the development of an epithermal neutron absolute flux intensity measurement technique has become crucial for real-time in-vivo dose monitoring in BNCT. In this study, a concept for a measurement system consisting of multiple compact scintillator with optical fibers detectors covered with neutron absorbers of various thicknesses is proposed. The designed system achieves a consistent response to epithermal neutrons with a theoretical coefficient of variation not higher than 5% for both LiCAF and EJ-254 scintillators. The theoretical feasibility of the proposed measurement system was investigated by an irradiation experiment carried out at the heavy water neutron irradiation facility at the Kyoto University Reactor. The experimental results indicated that further improvement and refinement are necessary to meet the high accuracy and precision required for real-time dose monitoring in clinical applications.

Level of expression of MHCI-presented neoepitopes influences tumor rejection by neoantigen-specific CD8+ T cells.

Neoantigen-targeted therapy holds an array of benefits for cancer immunotherapy, but the identification of peptide targets with tumor rejection capacity remains a limitation. To better define the criteria dictating tumor rejection potential, we examined the capacity of high-magnitude T cell responses induced towards several distinct neoantigen targets to regress MC38 tumors. Surprisingly, despite their demonstrated immunogenicity, vaccine-induced T-cell responses were unable to regress established MC38 tumors or prevent tumor engraftment in a prophylactic setting. However, T cells were functional with robust killing capacity towards neoantigen peptide-loaded cells. Furthermore, tumor cell killing was rescued in proportion to the expression level or saturation of target peptide-loaded MHCs on the cell surface. Overall, this study demonstrates a pivotal role for target protein expression levels in modulating the tumor rejection capacity of neoantigens. Thus, inclusion of this metric, in addition to immunogenicity analysis, may benefit antigen prediction techniques to ensure the full anti-tumor effect of cancer vaccines.

A red cell membrane-camouflaged nanoreactor for enhanced starvation/chemodynamic/ion interference therapy for breast cancer

In this study, a multifunctional Cu-doped CaO2 nanoreactor loaded with GOx and camouflaged with a folic acid-modified cell membranewas developed for breast cancer treatment. The as-developed composite nanoreactor showed a synergistic effect on calcium overload to damage mitochondria, thus killing tumor cells to achieve ion interference therapy (IIT). The loaded GOx could deplete glucose to “starve” tumor cells. The H2O2 released by CaO2 decomposition and enzyme catalytic reactions from GOx could not only be highly toxic in the tumor microenvironment but also enhance the efficiency of chemodynamic therapy (CDT) with Cu2+. The red blood cell membranes modified by folic acid achieved a combination of active targeting and passive targeting, thereby enhancing the targeting ability of the as-prepared multifunctional composite nanoreactor and prolonging its retention time at the tumor sites for more than 48 h.

Construction of self-driving anti-αFR CAR-engineered NK cells based on IFN-γ and TNF-α synergistically induced high expression of CXCL10

IntroductionOvarian cancer is the most malignant gynecological tumor. Previous studies have demonstrated that chimeric antigen receptor (CAR)-engineered NK-92 cells targeting folate receptor α (αFR) (NK-92-αFR-CAR) can specifically kill αFR-positive ovarian cancer cells. However, the migration barrier restricts antitumor effects of CAR-engineered cells. ObjectivesTo elucidate the mechanism by which NK-92-αFR-CAR cells induce the secretion of chemokine CXCL10 during killing ovarian cancer cells. It is speculated that NK-92-αFR-CAR-CXCR3A can target αFR and have chemotaxis of CXCL10, and they may have stronger killing effect of ovarian cancer. MethodsStudy the mechanism of CXCL10 expression strongly induced by TNF-α and IFN-γ combined stimulation in ovarian cancer cells. Construct the fourth generation of NK-92-αFR-CAR-CXCR3A cells, which were co-expressed CXCR3A and αFR-CAR. Evaluate the killing and migration effects of NK-92-αFR-CAR-CXCR3A in vitro and in vivo. ResultsRNA sequencing (RNA-seq) first revealed that the expression level of the chemokine CXCL10 was most significantly increased in ovarian cancer cells co-cultured with NK-92-αFR-CAR. Secondly, cytokine stimulation experiments confirmed that IFN-γ and TNF-α secreted by NK-92-αFR-CAR synergistically induced high CXCL10 expression in ovarian cancer cells. Further signaling pathway experiments showed that IFN-γ and TNF-α enhanced the activation level of the IFN-γ-IFNGR-JAK1/2-STAT1-CXCL10 signaling axis. Cytotoxicity experiments showed that NK-92-αFR-CAR-CXCR3A cells could not only efficiently kill αFR-positive ovarian cancer cells in vitro but also secrete IFN-γ and TNF-α. Higher migration than that of NK-92-αFR-CAR was detected in NK-92-αFR-CAR-CXCR3A using transwell assay. NK-92-αFR-CAR-CXCR3A effectively killed tumor cells in different mouse xenograft models of ovarian cancer and increased infiltration into tumor tissue. ConclusionThis study confirmed that IFN-γ and TNF-α secreted by αFR-CAR-engineered NK cells can synergistically induce high expression of CXCL10 in ovarian cancer cells and constructed self-driving αFR-CAR-engineered NK cells that can break through migration barriers based on CXCL10, which may provide a new therapeutic weapon for ovarian cancer.

INTASYL self-delivering RNAi decreases TIGIT expression, enhancing NK cell cytotoxicity: a potential application to increase the efficacy of NK adoptive cell therapy against cancer

Natural killer (NK) cells are frontline defenders against cancer and are capable of recognizing and eliminating tumor cells without prior sensitization or antigen presentation. Due to their unique HLA mismatch tolerance, they are ideal for adoptive cell therapy (ACT) because of their ability to minimize graft-versus-host-disease risk. The therapeutic efficacy of NK cells is limited in part by inhibitory immune checkpoint receptors, which are upregulated upon interaction with cancer cells and the tumor microenvironment. Overexpression of inhibitory receptors reduces NK cell-mediated cytotoxicity by impairing the ability of NK cells to secrete effector cytokines and cytotoxic granules. T-cell immunoreceptor with immunoglobulin and ITIM domains (TIGIT), a well-known checkpoint receptor involved in T-cell exhaustion, has recently been implicated in the exhaustion of NK cells. Overcoming TIGIT-mediated inhibition of NK cells may allow for a more potent antitumor response following ACT. Here, we describe a novel approach to TIGIT inhibition using self-delivering RNAi compounds (INTASYL™) that incorporates the features of RNAi and antisense technology. INTASYL compounds demonstrate potent activity and stability, are rapidly and efficiently taken up by cells, and can be easily incorporated into cell product manufacturing. INTASYL PH-804, which targets TIGIT, suppresses TIGIT mRNA and protein expression in NK cells, resulting in increased cytotoxic capacity and enhanced tumor cell killing in vitro. Delivering PH-804 to NK cells before ACT has emerged as a promising strategy to counter TIGIT inhibition, thereby improving the antitumor response. This approach offers the potential for more potent off-the-shelf products for adoptive cell therapy, particularly for hematological malignancies.

The relevance of tumor target expression levels on IgA-mediated cytotoxicity in cancer immunotherapy

Recent advances in cancer immunotherapy, particularly the success of immune checkpoint inhibitors, have reignited interest in targeted monoclonal antibodies for immunotherapy. Antibody therapies aim to minimize on-target, off-tumor toxicity by targeting antigens overexpressed on tumor cells but not on healthy cells. Despite considerable efforts, some therapeutic antibodies have been linked to dose-limiting side effects. Our hypothesis suggests that the efficacy of IgG leads to a lower target expression threshold for tumor cell killing, contributing to these side effects. Earlier, therapeutic IgG antibodies were reformatted into the IgA isotype. Unlike IgG, which primarily engages Fc gamma receptors (FcγR) to induce antibody-dependent cellular cytotoxicity (ADCC) by NK cells and antibody-dependent cellular phagocytosis (ADCP) by monocytes/macrophages, IgA antibodies activate neutrophils through the Fc alpha receptor I (CD89, FcαRI). In previous studies, it appeared that IgA may require a higher target expression threshold for effective killing, and we aimed to investigate this in our current study. Moreover, we investigated how blocking the myeloid checkpoint CD47/SIRPα axis affect the target expression threshold. Using a tetracycline-inducible expression system, we regulated target expression in different cell lines. Our findings from ADCC assays indicate that IgA-mediated PMN ADCC requires a higher antigen expression level than IgG-mediated PBMC ADCC. Furthermore, blocking CD47 enhanced IgA-mediated ADCC, lowering the antigen threshold. Validated in two in vivo models, our results show that IgA significantly reduces tumor growth in high-antigen-expressing tumors without affecting low-antigen-expressing healthy tissues. This suggests IgA-based immunotherapy could potentially minimize on-target, off-tumor side effects, improving treatment efficacy and patient safety.

IRF2 loss is associated with reduced MHC I pathway transcripts in subsets of most human cancers and causes resistance to checkpoint immunotherapy in human and mouse melanomas

BackgroundIn order for cancers to progress, they must evade elimination by CD8 T cells or other immune mechanisms. CD8 T cells recognize and kill tumor cells that display immunogenic tumor peptides bound to MHC I molecules. One of the ways that cancers can escape such killing is by reducing expression of MHC I molecules, and loss of MHC I is frequently observed in tumors. There are multiple different mechanisms that can underly the loss of MHC I complexes on tumor and it is currently unclear whether there are particular mechanisms that occur frequently and, if so, in what types of cancers. Also of importance to know is whether the loss of MHC I is reversible and how such loss and/or its restoration would impact responses to immunotherapy. Here, we investigate these issues for loss of IRF1 and IRF2, which are transcription factors that drive expression of MHC I pathway genes and some killing mechanisms.MethodsBioinformatics analyses of IRF2 and IRF2-dependent gene transcripts were performed for all human cancers in the TCGA RNAseq database. IRF2 protein-DNA-binding was analyzed in ChIPseq databases. CRISRPcas9 was used to knock out IRF1 and IRF2 genes in human and mouse melanoma cells and the resulting phenotypes were analyzed in vitro and in vivo.ResultsTranscriptomic analysis revealed that IRF2 expression was reduced in a substantial subset of cases in almost all types of human cancers. When this occurred there was a corresponding reduction in the expression of IRF2-regulated genes that were needed for CD8 T cell recognition. To test cause and effect for these IRF2 correlations and the consequences of IRF2 loss, we gene-edited IRF2 in a patient-derived melanoma and a mouse melanoma. The IRF2 gene-edited melanomas had reduced expression of transcripts for genes in the MHC I pathway and decreased levels of MHC I complexes on the cell surface. Levels of Caspase 7, an IRF2 target gene involved in CD8 T cell killing of tumors, were also reduced. This loss of IRF2 caused both human and mouse melanomas to become resistant to immunotherapy with a checkpoint inhibitor. Importantly, these effects were reversible. Stimulation of the IRF2-deficient melanomas with interferon induced the expression of a functionally homologous transcription factor, IRF1, which then restored the MHC I pathway and responsiveness to CPI.ConclusionsOur study shows that a subset of cases within most types of cancers downregulates IRF2 and that this can allow cancers to escape immune control. This can cause resistance to checkpoint blockade immunotherapy and is reversible with currently available biologics.

Branched oncolytic peptides target HSPGs, inhibit metastasis, and trigger the release of molecular determinants of immunogenic cell death in pancreatic cancer.

Immunogenic cell death (ICD) can be exploited to treat non-immunoreactive tumors that do not respond to current standard and innovative therapies. Not all chemotherapeutics trigger ICD, among those that do exert this effect, there are anthracyclines, irinotecan, some platinum derivatives and oncolytic peptides. We studied two new branched oncolytic peptides, BOP7 and BOP9 that proved to elicit the release of damage-associated molecular patterns DAMPS, mediators of ICD, in pancreatic cancer cells. The two BOPs selectively bound and killed tumor cells, particularly PANC-1 and Mia PaCa-2, but not cells of non-tumor origin such as RAW 264.7, CHO-K1 and pgsA-745. The cancer selectivity of the two BOPs may be attributed to their repeated cationic sequences, which enable multivalent binding to heparan sulfate glycosaminoglycans (HSPGs), bearing multiple anionic sulfation patterns on cancer cells. This interaction of BOPs with HSPGs not only fosters an anti-metastatic effect in vitro, as demonstrated by reduced adhesion and migration of PANC-1 cancer cells, but also shows promising tumor-specific cytotoxicity and low hemolytic activity. Remarkably, the cytotoxicity induced by BOPs triggers the release of DAMPs, particularly HMGB1, IFN-β and ATP, by dying cells, persisting longer than the cytotoxicity of conventional chemotherapeutic agents such as irinotecan and daunorubicin. An in vivo assay in nude mice showed an encouraging 20% inhibition of tumor grafting and growth in a pancreatic cancer model by BOP9.